Re: [PATCH 05/19] x86/dumpstack: fix function graph tracing stack dump reliability issues

From: Josh Poimboeuf
Date: Tue Aug 02 2016 - 23:31:38 EST


On Tue, Aug 02, 2016 at 11:21:04PM -0400, Steven Rostedt wrote:
> On Tue, 2 Aug 2016 23:18:57 -0400
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> > On Tue, 2 Aug 2016 22:12:33 -0500
> > Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >
> >
> > > Sounds good. I was thinking I could also add a similar define to
> > > indicate whether an arch passes the return address stack pointer to
> > > ftrace_push_return_trace(). HAVE_FUNCTION_GRAPH_RET_ADDR_PTR?
> > >
> >
> > If you are making this function global, might as well make all pass
> > that pointer when you do the conversion. I don't think we need a define
> > to differentiate it.
> >
>
> Bah, I was thinking of your ftrace_graph_ret_addr() function. /me needs
> to go to bed.
>
> Anyway, if we have to add a parameter, we probably need to update all
> the callers anyway. We do need to add a parameter for this, right?

Yeah, we do need to add a parameter to ftrace_push_return_trace(). But
callers which don't implement it could just pass zero like they do with
'fp'.

--
Josh